The present invention relates to systems and methods for cleaning materials.
Materials such as carpets produced from synthetic or natural fibers and mixtures thereof are commonly used in residential and commercial applications as a floor covering. Various types of fibers can be used in making carpets such as polyamide and wool. However, carpets irrespective of whether they are made from natural or synthetic fibers are all prone to soiling and staining when contacted with many household items. Foods, grease, oils, beverages such as coffee, tea and soft drinks especially those containing acidic dyes can cause unsightly, often dark stains on carpets. Also fibers may become soiled as a result of dirt particles, clay, dust, particulate soils in general, coming into contact with, and adhering to the fibers of the carpet. These latter soils often appear in the form of a diffuse layer of soils rather than in the form of spots and tend to accumulate particularly in the so called “high traffic areas” such as near doors as a result of intensive use of the carpets in such areas.
Carpet cleaning and maintenance conventionally involves the application of a detergent solution to the carpet followed by extraction. Detergents, however, are alkaline and are often the cause of re-soiling. Detergents also work best at very high temperatures, this can cause carpet to delaminate. The job of a detergent is to release dirt's and oils from the carpet surface, they are able to do this because they contain surfactants (short for surface acting agents). Surfactants are molecules that are both Hydrophilic (water soluble) and Hydrophobic (water insoluble). These molecules have the ability to lower the surface tension of water and emulsify (saturate) the surface that is being cleaned. This causes the dirt and oils to release from the surface they are attached to. Dirt and oil is hydrophobic, when it is released into liquid it is naturally attracted to other hydrophobic particles. Surfactants are half hydrophobic so they attach themselves to the dirt and oil, they are also hydrophilic so they are able to keep the dirt and oil suspended in liquid.
Surfactants found in detergents are made of petroleum distillates, natural fats and oils, short synthetic polymers, or large synthetic alcohols. These surfactants require certain conditions in order to function efficiently, high temperature and a ph of 9 or greater. This puts them on the alkaline side of the ph scale. Solutions that are alkaline are sticky and slimy by nature, this is why it is necessary to rinse well after using detergents otherwise they will leave a sticky alkaline residue that will attract more dirt. This is a bit of a problem when it comes to carpet cleaning because carpet is absorbent by nature and difficult to rinse without using large amounts of water, and wet indoor carpet is a haven for the growth of mold, mildew, and bacteria.
Biosurfactants are a structurally diverse group of surface-active molecules synthesized by microorganisms. Biosurfactants are amphipathic molecules consisting of both hydrophobic and hydrophilic domains. Due to their amphipathic nature, biosurfactants can partition at the interfaces between different fluid phases such as oil/water or water/air interfaces. Unlike synthetic surfactants, biosurfactants are effective in hot or cold water, and at either extreme of the ph scale. Classifications of biosurfactants include: Glycolipids, Rhamnolipids, Trehalolipids, Sophorolipids, lipopepdides, and lipoproteins.